Transport in deformable hygroscopic porous media during microwave puffing

Abstract

Microwave puffing is a process used to obtain low‐fat healthy foods by rapid heating of food products to develop high internal pressures in the material that cause significant structural changes. Two‐way coupling of complex multiphase transport and large deformations in the material, which is critical to simulate the puffing process accurately, was implemented. A porous media model that includes different phases, solid, liquid water, and gas, and incorporates pressure driven flow and evaporation was used to describe the transport processes in the material. Large deformations were included to model structural changes, with the material treated as hyperelastic. Arbitrary Lagrangian–Eulerian (ALE) framework was used. The model was validated using experimental temperature, moisture, and volume measurement and used to comprehensively understand the puffing process. Uncertainty analysis was carried out to estimate uncertainty in model prediction due to the choice of critical input parameters such as bulk modulus and permeabilities. © 2012 American Institute of Chemical Engineers AIChE J, 59: 33–45, 2013

Amylose content and micromorphology of popcorn progenies with different popping expansion volumes

“…The popcorn kernel pericarp not only provides protection and containment to the endosperm, but also acts as a pressure vessel during heating, which gives popcorn its characteristic popping ability (PEREIRA et al, 2008). As heat is applied to popcorn, the pericarp limits kernel moisture loss and facilitates vapor pressure build-up and water superheating within the kernels (RAKESH et al, 2013). SWELEY et al (2013) suggested the use of pericarp thickness as an indicator of popping quality.…”

Multiphysics Modeling of Microwave Heating of a Frozen Heterogeneous Meal Rotating on a Turntable

“…The limited reported data are for raw potato (Ni and Datta ; Datta ), meat (Datta ), bread (Goedeken and Tong ), and apple (Feng and others ). In porous media transport modeling, researchers have used a wide range of water and gas permeability values that can vary by more than 2 orders of magnitude from 10 −14 to 10 −17 m 2 for different food products (Halder and others 2007a; Dhall and others ; Rakesh and Datta ). In this study, we used 10 −15 and 10 −14 m 2 for intrinsic permeability of water and gas, respectively, which are in range of reported values in the literature.…”

“…The diffusion coefficient is a strong function of moisture content, temperature, and structure (void fraction, prestructure, and distribution) of the material (Gulati and Datta ). Different diffusion coefficients of water and gas have been used in modeling of different process of different food products, varying from 10 −7 to 10 −8 m 2 /s for liquid water (Rakesh and Datta , ; Dhall and others ; Warning and others ), and from 10 −5 to 10 −6 m 2 /s for water gas (Halder and others 2007a; Rakesh and Datta , ; Dhall and others ). In this study we used the value of 1 × 10 −7 .exp (−2.8 + 2M) for liquid water and 2.6 × 10 −5 m 2 /s for gas, which were reasonable estimations.…”

“…In this study, we included magnetron as a coaxial power source which generates TEM mode inside the cavity. In literature (Halder and others 2007a, ; Rakesh and others ; Warning and others ), the boundary condition for Darcy's law was applied by setting the boundary pressure to be the ambient pressure. In our model development, the Darcy's pressure was calculated by the ideal gas law based on the vapor and air concentrations.…”

“…A multiphase porous media model combining the electromagnetic heat source with heat and mass transfer, and including phase change of water during evaporation, is needed to accurately describe the microwave heating process. A very few comprehensive multiphase porous media models have been developed to study various heating processes such as conventional cooking (Dhall and others ), frying (Halder and others 2007a, 2007b, ), and microwave puffing (Rakesh and Datta , ). These models coupled different types of heating sources with heat and mass transfer for different food processes.…”